This proposal is the second submission of a competing renewal to continue our investigations into the neurobiological basis for sex differences in ethanol dependence and withdrawal. To date, we have identified important differences between male and female rats in adaptations of GABA-A and NMDA receptors during ethanol dependence and early withdrawal across several brain sites. We recently found significant and robust behavioral sex differences in the timing for recovery from ethanol withdrawal. Whereas both males and females showed significant withdrawal signs at 24 hr, females, but not males, appeared to have recovered by 3 days. Therefore, the overall goal of this project is to elucidate the mechanistic underpinnings for behavioral expressions of ethanol withdrawal at 24 hr and 3 days. We hypothesize that differences in recovery from ethanol withdrawal involve sex-selective changes in GABAergic and glutamatergic neurotransmission that occur as a result of the differing hormonal milieu between males and females. To test this hypothesis we will compare and contrast findings in young adult male, cycling diestrus female and ovariectomized female rats. The proposed studies will allow us to delineate the importance of hormonal modulation in conferring sex differences in recovery from ethanol withdrawal. This project will test the hypothesis by these aims: 1. assessment of several ethanol withdrawal behaviors, including responses to drug treatments, at early (24 hr) and later (3 days) withdrawal, 2. identification of concomitant sex differences in brain activation with analysis of modulation of GABA-A and NMDA receptors at these same times of withdrawal, and 3. analysis of ethanol withdrawal-induced changes in GABA, glutamate and steroid levels. We expect to find that the differing hormonal milieu between males and cycling females regulates adaptations of GABAergic and glutamatergic neurotransmission that confers recovery from ethanol withdrawal. Findings resulting from these proposed studies should show that inherent, neurobiological regulation due to hormonal status is an important factor influencing actions of ethanol, with adaptations being different for recovery than development of dependence. Increasing our understanding of sex-selective mechanism underlying withdrawal should help guide us towards improving treatments for alcohol withdrawal in both women and men.